<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: ZendPlatform.php 16971 2009-07-22 18:05:45Z mikaelkael $
 */

/**
 * @see Zend_Cache_Backend_Interface
 */
require_once 'Zend/Cache/Backend.php';

/**
 * @see Zend_Cache_Backend_Interface
 */
require_once 'Zend/Cache/Backend/Interface.php';


/**
 * Impementation of Zend Cache Backend using the Zend Platform (Output Content Caching)
 *
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Cache_Backend_ZendPlatform extends Zend_Cache_Backend implements Zend_Cache_Backend_Interface
{
	/**
	 * internal ZP prefix
	 */
	const TAGS_PREFIX = "internal_ZPtag:";

	/**
	 * Constructor
	 * Validate that the Zend Platform is loaded and licensed
	 *
	 * @param  array $options Associative array of options
	 * @throws Zend_Cache_Exception
	 * @return void
	 */
	public function __construct(array $options = array())
	{
		if (!function_exists('accelerator_license_info')) {
			Zend_Cache::throwException('The Zend Platform extension must be loaded for using this backend !');
		}
		if (!function_exists('accelerator_get_configuration')) {
			$licenseInfo = accelerator_license_info();
			Zend_Cache::throwException('The Zend Platform extension is not loaded correctly: '.$licenseInfo['failure_reason']);
		}
		$accConf = accelerator_get_configuration();
		if (@!$accConf['output_cache_licensed']) {
			Zend_Cache::throwException('The Zend Platform extension does not have the proper license to use content caching features');
		}
		if (@!$accConf['output_cache_enabled']) {
			Zend_Cache::throwException('The Zend Platform content caching feature must be enabled for using this backend, set the \'zend_accelerator.output_cache_enabled\' directive to On !');
		}
		if (!is_writable($accConf['output_cache_dir'])) {
			Zend_Cache::throwException('The cache copies directory \''. ini_get('zend_accelerator.output_cache_dir') .'\' must be writable !');
		}
		parent:: __construct($options);
	}

	/**
	 * Test if a cache is available for the given id and (if yes) return it (false else)
	 *
	 * @param  string  $id                     Cache id
	 * @param  boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested
	 * @return string Cached data (or false)
	 */
	public function load($id, $doNotTestCacheValidity = false)
	{
		// doNotTestCacheValidity implemented by giving zero lifetime to the cache
		if ($doNotTestCacheValidity) {
			$lifetime = 0;
		} else {
			$lifetime = $this->_directives['lifetime'];
		}
		$res = output_cache_get($id, $lifetime);
		if($res) {
			return $res[0];
		} else {
			return false;
		}
	}


	/**
	 * Test if a cache is available or not (for the given id)
	 *
	 * @param  string $id Cache id
	 * @return mixed|false false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	public function test($id)
	{
		$result = output_cache_get($id, $this->_directives['lifetime']);
		if ($result) {
			return $result[1];
		}
		return false;
	}

	/**
	 * Save some string datas into a cache record
	 *
	 * Note : $data is always "string" (serialization is done by the
	 * core not by the backend)
	 *
	 * @param  string $data             Data to cache
	 * @param  string $id               Cache id
	 * @param  array  $tags             Array of strings, the cache record will be tagged by each string entry
	 * @param  int    $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
	 * @return boolean true if no problem
	 */
	public function save($data, $id, $tags = array(), $specificLifetime = false)
	{
		if (!($specificLifetime === false)) {
			$this->_log("Zend_Cache_Backend_ZendPlatform::save() : non false specifc lifetime is unsuported for this backend");
		}

		$lifetime = $this->_directives['lifetime'];
		$result1  = output_cache_put($id, array($data, time()));
		$result2  = (count($tags) == 0);

		foreach ($tags as $tag) {
			$tagid = self::TAGS_PREFIX.$tag;
			$old_tags = output_cache_get($tagid, $lifetime);
			if ($old_tags === false) {
				$old_tags = array();
			}
			$old_tags[$id] = $id;
			output_cache_remove_key($tagid);
			$result2 = output_cache_put($tagid, $old_tags);
		}

		return $result1 && $result2;
	}


	/**
	 * Remove a cache record
	 *
	 * @param  string $id Cache id
	 * @return boolean True if no problem
	 */
	public function remove($id)
	{
		return output_cache_remove_key($id);
	}


	/**
	 * Clean some cache records
	 *
	 * Available modes are :
	 * Zend_Cache::CLEANING_MODE_ALL (default)    => remove all cache entries ($tags is not used)
	 * Zend_Cache::CLEANING_MODE_OLD              => remove too old cache entries ($tags is not used)
	 *                                               This mode is not supported in this backend
	 * Zend_Cache::CLEANING_MODE_MATCHING_TAG     => remove cache entries matching all given tags
	 *                                               ($tags can be an array of strings or a single string)
	 * Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG => unsupported
	 * Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG => remove cache entries matching any given tags
	 *                                               ($tags can be an array of strings or a single string)
	 *
	 * @param  string $mode Clean mode
	 * @param  array  $tags Array of tags
	 * @throws Zend_Cache_Exception
	 * @return boolean True if no problem
	 */
	public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
	{
		switch ($mode) {
			case Zend_Cache::CLEANING_MODE_ALL:
			case Zend_Cache::CLEANING_MODE_OLD:
				$cache_dir = ini_get('zend_accelerator.output_cache_dir');
				if (!$cache_dir) {
					return false;
				}
				$cache_dir .= '/.php_cache_api/';
				return $this->_clean($cache_dir, $mode);
				break;
			case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
				$idlist = null;
				foreach ($tags as $tag) {
					$next_idlist = output_cache_get(self::TAGS_PREFIX.$tag, $this->_directives['lifetime']);
					if ($idlist) {
						$idlist = array_intersect_assoc($idlist, $next_idlist);
					} else {
						$idlist = $next_idlist;
					}
					if (count($idlist) == 0) {
						// if ID list is already empty - we may skip checking other IDs
						$idlist = null;
						break;
					}
				}
				if ($idlist) {
					foreach ($idlist as $id) {
						output_cache_remove_key($id);
					}
				}
				return true;
				break;
			case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
				$this->_log("Zend_Cache_Backend_ZendPlatform::clean() : CLEANING_MODE_NOT_MATCHING_TAG is not supported by the Zend Platform backend");
				return false;
				break;
			case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
				$idlist = null;
				foreach ($tags as $tag) {
					$next_idlist = output_cache_get(self::TAGS_PREFIX.$tag, $this->_directives['lifetime']);
					if ($idlist) {
						$idlist = array_merge_recursive($idlist, $next_idlist);
					} else {
						$idlist = $next_idlist;
					}
					if (count($idlist) == 0) {
						// if ID list is already empty - we may skip checking other IDs
						$idlist = null;
						break;
					}
				}
				if ($idlist) {
					foreach ($idlist as $id) {
						output_cache_remove_key($id);
					}
				}
				return true;
				break;
			default:
				Zend_Cache::throwException('Invalid mode for clean() method');
				break;
		}
	}

	/**
	 * Clean a directory and recursivly go over it's subdirectories
	 *
	 * Remove all the cached files that need to be cleaned (according to mode and files mtime)
	 *
	 * @param  string $dir  Path of directory ot clean
	 * @param  string $mode The same parameter as in Zend_Cache_Backend_ZendPlatform::clean()
	 * @return boolean True if ok
	 */
	private function _clean($dir, $mode)
	{
		$d = @dir($dir);
		if (!$d) {
			return false;
		}
		$result = true;
		while (false !== ($file = $d->read())) {
			if ($file == '.' || $file == '..') {
				continue;
			}
			$file = $d->path . $file;
			if (is_dir($file)) {
				$result = ($this->_clean($file .'/', $mode)) && ($result);
			} else {
				if ($mode == Zend_Cache::CLEANING_MODE_ALL) {
					$result = ($this->_remove($file)) && ($result);
				} else if ($mode == Zend_Cache::CLEANING_MODE_OLD) {
					// Files older than lifetime get deleted from cache
					if ($this->_directives['lifetime'] !== null) {
						if ((time() - @filemtime($file)) > $this->_directives['lifetime']) {
							$result = ($this->_remove($file)) && ($result);
						}
					}
				}
			}
		}
		$d->close();
		return $result;
	}

	/**
	 * Remove a file
	 *
	 * If we can't remove the file (because of locks or any problem), we will touch
	 * the file to invalidate it
	 *
	 * @param  string $file Complete file path
	 * @return boolean True if ok
	 */
	private function _remove($file)
	{
		if (!@unlink($file)) {
			# If we can't remove the file (because of locks or any problem), we will touch
			# the file to invalidate it
			$this->_log("Zend_Cache_Backend_ZendPlatform::_remove() : we can't remove $file => we are going to try to invalidate it");
			if ($this->_directives['lifetime'] === null) {
				return false;
			}
			if (!file_exists($file)) {
				return false;
			}
			return @touch($file, time() - 2*abs($this->_directives['lifetime']));
		}
		return true;
	}

}
